I don't seem to receive any periodical multicast DNS-SD advertisements for Authorization server mock up

[akanashin]

Hey!

I'm working on DNS-SD cache. For now it only works as multicast.
And what I do observe:

• I work with services _nmos-auth._tcp and _nmos-register._tcp
• First I start to request data about the services, then I start to listen on multicast DNS port dedicated for this
• when I send request I receive A,PTR,SRV and TXT records for all services available at the time
• then when tests are active I receive updates for Register service (expirations, new tests active, etc...)
• however, I never receive any updates on Authorization server mockup

As result, at some point records A and SRV for the service expire and my program is left with nowhere to go unless I perform new request.

I see this quote

The preferred method of Authorization API advertisement is via unicast DNS-SD advertisement of the type _nmos-auth._tcp. Authorization APIs SHOULD additionally be capable of producing an mDNS advertisement. This MAY be disabled via a user-configurable method.

I guess that I need to implement unicast DNS-SD but in the meantime It does not look like multicast should not work at all.

So the questions:

• Is this intended behaviour and I have to work with Authorization service via unicast DNS-SD only?
• (or) I need to enable/disable some flag for the testing utility?
• (or) any other option?

Thanks

[lo-simon]

You will need to set CONFIG.ENABLE_AUTH = True in your nmos-testing config. You will be able to browse the mock Auth service after restarting the nmos-testing.

[akanashin]

It's already on. Also, DNS-SD is in multicast mode.

Just in case, does in have anything with the fact that the testing utility is working in docker image with --network=host option?

[lo-simon]

I am not sure about the Docker image; I use nmos-testing from source.

[garethsb]

If we'e talking about mDNS, the spec (RFC 6762) says that a responder (e.g. the Testing Tool) should only announce itself when it starts up, it MUST NOT send unsolicited announcements again unless its records need to change. A querier (your app) should issue a new query after approx. 80% of the TTL. The spec has the precise details.

[garethsb]

If the Testing Tool is only making unsolicited announcements and isn't responding to queries, then that would be a bug in the mDNS implementation in the Testing Tool, but since you mention periodical advertisements, I wonder if you're expecting unsolicited re-advertisements, which are prohibited by the mDNS spec.